two NICs and speed issues

[Chadley Wilson]

What is your gateway?
Have your checked your routing tables, and your firwall?

I don't know how to setup the iptables my self but I have seeen this
cause by that before.
let us know will ya!

On Mon, 2004-07-19 at 16:04, Scot L. Harris wrote:
> On Mon, 2004-07-19 at 09:45, sam at illawarra.org wrote:
> > Hi,
> > 
> > i'm running Fedora Core 2 on my server - which, for the most past works
> > quite well.. kudos to the dev team. However, i have a minor problem i
> > cannot seem to fix and is thus:
> > 
> > i have two network cards ( sis900 and usb200m ) and the first is connected
> > to my dsl300+ (dlink) modem at 10mbit and the other is connected to a
> > 10/100 switch that feeds the local lan. if i unplug the dsl300+ from the
> > rj45 my local lan works quite fast 8MBytes ftp transfers etc to the local
> > net via the usb200m. however if i plug the modem in i only get 120kbyte
> > transfer speeds and such. i have switched the modem to the other nic and
> > the same thing happens. for some odd reason i can only get good speeds to
> > / from the server to the local net if i only make the local net nic 10mbit
> > with mii-tool OR unplug the modem and thus get 100mbit speeds..
> > 
> > help!
> > 
> > regards,
> > Sam.
> 
> So if you disconnect the modem (10Mbit) the transfers are fast on the
> LAN side.  And if you set the LAN NIC to 10Mbit and connect the modem to
> the other NIC your transfer speeds are fast?
> 
> Have you looked at the stats on the interfaces to see if you are taking
> any errors?
> 
> ifconfig -a
> 
> will give you a listing of each interface.  Pay attention to the RX and
> TX lines, you will see counters for errors, dropped, overruns, and
> frame.  If for some reason you are getting errors on packets they will
> be retransmitted.  Lots of errors will result in very poor performance
> but the transfer will still get through due to the TCP/IP protocol.  
> 
> Also what type of switch are you using?  I have seen some switches that
> have problems negotiating the right settings.  When using 100Mbit
> connections you want to have full duplex set.  For 10Mbit connections
> half duplex is usually the default.  If you have a duplex problem
> between the NIC and the switch you will see the error count increase
> during a transfer.
> 
> >From the description it almost sounds like the interface connecting to
> the modem is forcing either duplex or speed settings on the other
> interface.  Have you checked that using mii-tool in both configurations?
> -- 
> Scot L. Harris
> webid at cfl.rr.com
> 
> It's not hard to admit errors that are [only] cosmetically wrong.
> 		-- J.K. Galbraith 
-- 
******************************************************************
Chadley Wilson
Soon 2 B RHCE
Linux Rocks
Welcome to my world.
Enjoy the adventures of Linux 
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Linux is easy, lazy people criticise, curse and fail.